Water-in-oil emulsions have found wide acceptance as fire-resistant hydraulic fluids in general industry, coal mines and rolling mills where fire hazards exist. These hydraulic fluids are generally used in applications where the fluid could spray or drip from a break or leak onto a source of ignition, e.g., a pot of molten metal or a gas flame. This condition often exists in die-casting machines or in presses located near furnaces. Typically, these hydraulic fluids are constituted of a continuous oil phase, a discontinuous aqueous phase, at least one emulsifying agent, and one or more functional additives such as rust-inhibiting agents, extreme-pressure agents, foam inhibitors, freezing point depressants, bactericides, oxidation inhibitors, and the like. Examples of such hydraulic fluids are disclosed in U.S. Pat. Nos. 3,255,108; 3,269,946; 3,281,356; 3,311,4561; 3,378,494; 3,629,119; and 4,225,447; these patents being incorporated herein by reference.
A problem with water-in-oil hydraulic fluids is that they have a tendency to cause wear of metallic pump parts and other equipment with which they come into contact. The water phase, though dispersed in the oil phase, creates wear problems that are not encountered with straight petroleum oil compositions. Another problem is that the water phase tends to corrode the metallic parts it contacts. Water-phase additives which have been employed previously to reduce wear and/or corrosion have had the disadvantage that they tend to precipitate from the emulsion, particularly when the water content becomes reduced during use. The omission of water-phase additives, on the other hand, is undesirable since it is frequently impossible to obtain satisfactory wear- and/or corrosion-resistance by the use of additives which are dissolved only in the oil phase.
Explosive emulsions are typically constituted of continuous organic fuel or oil phase in which discrete droplets of an aqueous solution of an oxygen-supplying source are dispersed as a discontinuous phase. Such compositions are conventionally described as water-in-oil explosive emulsion compositions, and examples thereof have been described, inter alia, in U.S. Pat. Nos. 3,447,978; 3,985,593; 4,008,110; 4,097,316; 4,104,092; 4,110,134; 4,149,916; 4,149,917; 4,218,272; 4,259,977; 4,357,184; 4,371,408; 4,404,050; 4,409,044; 4,453,989; and 4,534,809; and European Application Publication No. 0,155,800 Al, which are incorporated herein by reference. Formation of these explosive emulsions is generally effected in the presence of an emulsifier which is selected to promote subdivision of the droplets of the oxidizer phase and dispersion thereof in the continuous phase. While many of the emulsifiers described in the prior art are meritorious, none have provided emulsion stability characteristics that are entirely satisfactory. Additionally, with most emulsifiers used in the prior art, selection of the fuel or oil for the continuous phase is generally limited to highly-refined, highly paraffinic oils such as white oils.
Acid treating or acidizing of porous subterranean formations penetrated by a well bore has been widely employed for increasing the production of fluids, e.g., crude oil, natural gas, etc., from the formations. The usual technique of acidizing a formation comprises introducing a nonoxidizing acid into the well under sufficient pressure to force the acid out into the formation where it reacts with the acid-soluble components of the formation. The technique is applicable to formations of high acid solubility such as limestone, dolomite, etc., as well as to other types of formations such as a sandstone containing streaks or striations of acid-soluble components such as the various carbonates. During the acid treating operation, passageways for fluid flow are created in the formation, or existing passageways therein are enlarged, thus stimulating the production of fluids from the formation. This action of the acid on the formation is often called etching. Acid treating or acidizing operations wherein the acid is injected into the formation at a pressure or rate insufficient to create cracks or fractures in the formation is usually referred to as matrix-acidizing. Various acidizing compositions have been disclosed in the prior art. Examples are disclosed, inter alia, in U.S. Pat. Nos. 4,136,739; 4,137,182; 4,137,400; 4,137,972; 4,143,007; 4,144,179; 4,146,486; 4,148,360; 4,148,736; 4,151,098; 4,152,274; 4,152,289; 4,153,066; 4,153,649; 4,160,483; 4,163,727; 4,167,214; 4,169,797; 4,169,798; 4,169,818; 4,169,945; 4,172,041; 4,172,055; 4,174,283; 4,191,657; 4,200,151; 4,200,539; 4,200,540; 4,202,795; 4,203,492; 4,205,724; 4,206,058; 4,210,205; 4,210,206; 4,215,001; 4,217,231; 4,219,429; 4,225,445; 4,244,826; and 4,246,124, these patents being incorporated herein by reference. Examples of water-in-oil emulsions used in acidizing are disclosed in U.S. Pat. Nos. 4,140,640 and 4,233,165, which are incorporated herein by reference.
Hydrocarbyl-substituted carboxylic acylating agents having at least 30 aliphatic carbon atoms in the substituent are known. The use of such carboxylic acylating agents as additives in normally liquid fuels and lubricants is discussed in U.S. Pat. Nos. 3,288,714 and 3,346,354. These acylating agents are also useful as intermediates for preparing additives for use in normally liquid fuels and lubricants as described in U.S. Pat. Nos. 2,892,786; 3,087,936; 3,163,603; 3,172,892; 3,189,544; 3,215,707; 3,219,666; 3,231,587; 3,235,503; 3,272,746; 3,306,907; 3,306,908; 3,331,776; 3,341,542; 3,346,354; 3,374,174; 3,379,515; 3,381,022; 3,413,104; 3,450,715; 3,454,607; 3,455,728; 3,476,686; 3,513,095; 3,523,768; 3,630,904; 3,632,511; 3,697,428; 3,755,169; 3,804,763; 3,836,470; 3,862,981; 3,936,480; 3,948,909; 3,950,341; 4,234,435; and 4,471,091; and French Patent No. 2,223,415.
Nitrogen-containing, phosphorus-free carboxylic solubilizers useful in high water based functional fluids are disclosed in U.S. Pat. Nos. 4,329,249; 4,368,133; 4,435,297; 4,447,348; and 4,448,703. These solubilizers are made by reacting (I) at least one carboxylic acid acylating agent having at least one hydrocarbyl-based substituent of at least about 12 to about 500 carbon atoms with (II) at least one (a) N-(hydroxyl-substituted hydrocarbyl) amine, (b) hydroxyl-substituted poly(hydrocarbyloxy) analog of said amine (a), or (c) mixtures of (a) and (b). These patents indicate that the preferred acylating agents include the substituted succinic acids or anhydrides and that the amines that are useful include the primary, secondary and tertiary alkanol amines. These solubilizers are useful in dispersing or dissolving oil-soluble, water-insoluble functional additives in water-based functional fluids. These references indicate that a particularly preferred embodiment of the solubilizer is the reaction product of a polyisoubtenyl-substituted succinic anhydride with diethylethanolamine or a mixture of diethylethanolamine and ethanolamine.